Before buying ticket, it is always good to write down the things that you are going to say to the ticketing agent:
Departure date
Departure time
Departure place
Where exactly you want to get off the bus
Number of passengers
Front seat (if you prefer that)

Buy ticket from company that
a) has its own platform, not shared platform.
b) will not stop elsewhere for more passenger pickup.

If your destination is on the route of coach buses (for example your house is located before the destination bus station), choose a bus that can let you get off exactly at the place.
You do not want a bus that has the final stop a few kilometers before your desired destination.

If you are going to come back, remember to buy round-trip tickets so that you do not have to think about buying ticket again.
But you have to be firm on your return date.

Bring along something that will relieve dizziness just in case.
You do not know the condition of the bus or the skill of the driver.

If the day that you are going to travel is in the beginning or the end of the festive or holiday season, be sure to travel in the morning.
You do not want to be caught in the traffic jam.

To lower the risk of road traveling, try not to travel at night.

Before you depart from house, make a quick call to the bus terminal to check if the bus is delayed.

Unless the bus station is within walking distance or rather near from where you live, you should plan your traveling time to reach the bus station half an hour to an hour earlier than the departure time.
This is to consider the possibility of delay such as traffic jam.
You will have the peace of mind if you have ample time to reach the bus station.
You can do many things while you wait for the departure time at the bus station such as reading newspapers or sending SMS to keep in touch with friends.

I personally avoid drinking much water (including soup) before the travel because the buses here do not have a toilet onboard.
Also before boarding I will go to the toilet even though I do not have the urge.
Even if I may request the driver to stop by a toilet later, but if there is heavy rain and I have no umbrella, I will not feel like running in the rain to go to the toilet.
Dilemma.

Go to the platform 10 minutes before the departure just in case if there is somebody who tells the change of boarding location.

If you are at the bus station and you discover that you miss the date or time but there is a bus from the same company which is going where you want to go, you can try talk to the bus conductor to let you board the bus if at the time of departure there is vacant seat.

It is good if you can jot down the bus number and the bus office phone number so that in case you accidentally leave something on the bus you can call the office to keep the things for you.

If you are traveling alone, say hi at least to your seatmate.
It is a rare occasion that you can be physically so close to a stranger for a significant period of time.

Expect the passenger right in front of you to budge down the seat back without telling you but you should tell passenger right behind you that you are going to shift down your seat back.

If you put valuables in your traveling pack, the traveling pack must be with you all the time especially when you want to leave your seat when the bus stops for a break.